Whats most cost effective in primer?

The state that my 59 rambler sits in currently, the front end is in black primer and there is some that was started on the drivers door (all done before I recived the car), there are panels where sanding has been done down to the metal. So before winter gets here I need to at least prime the rest of the car. What is the most cost effective manner to prime out the rest of the car? Rattle can, or something else. and if I go rattle can is the cheapest walmart primer ok or do I need to go with something else. Right now the exterior of the car is not my priority other than getting it one color minus fins and roof which will stay white.

photos of it currently are here Hot Rod Photo Journal - 59RAMBLERSUPERWAGON's Journal